Each compressed SSTable uses additional transfer buffer in
CompressedRandomAccessReader instance.
After analyzing Heap I saw this buffer has a size about 70KB per SSTable. I
have more than 30K SSTables per node.
I want to turn off a compression for this column family to save some Heap. How
can I do it safely? I mean after that the SCRUB/UPGRADESSTABLES process should
be started?
Next question is how do this processes work in terms of using disk space. I.e.
CLEANUP is safe - it takes one SSTable, analyzes keys, builds new one, replace
existing and goes further. Do SCRUB/UPGRADESSTABLES work in the same manner? My
concern is a disk space usage overhead.
